The invention relates to a miner especially adapted for high-production mining of low-coal seams (24-36 inches thick) while providing maximum miner safety and complying with applicable federal regulations, however, the miner may be used for mining thicker coal seams.
In the past, there have been problems associated with low-coal seam mining that have made high production mining difficult, such problems including proper roof supports, good cutting action of the cutting means, effective conveyance of the cut coal away from the cutting face, and proper dust control in the cutting area. While there have been recent proposals (such as shown in U.S. Pat. Nos. 3,640,580 and 3,784,256) for effecting dust control in seam mining in general, the prior proposed structures have been relatively complicated, too large and expensive, and the problems of proper roof support, good cutting action for effective high-production mining in low coal seams, and effective conveyance of coal away from the cutting face have not been entirely solved.
According to the present invention, a full face miner for mining coal or the like (especially in low seams) has been provided, including one or more cutting heads that are rotatable about vertical axes, the rotation about vertical axes providing effective cutting action, and an accessory cutting member is provided with each cutting head for providing slight adjustment of the height of the fact that is to be cut. Means are provided for rotating the cutting heads about their vertical axes -- so that the cutting heads rotate inwardly toward each other -- and means are provided for mounting the cutting heads for reciprocal longitudinal movement toward and away from each other along the cutting face. Means are provided for moving the cutting heads on the mounting means in the reciprocal longitudinal movement so that the cutting heads may move toward or away from each other to effect shearing so that the cut coal is continuously conveyed away by a paddle-type conveyor or the like. The conveyor moves the cut coal toward a mid-point of the cutting face and then conveys the coal away from the cutting face substantially perpendicular thereto.
Such conveying action allows conveyance of the coal away from the mined area through the tunnel already formed by the miner and it is not necessary to provide any communication between the ends of the face and accessory-conveying means, as is necessary in forms of conventional long-wall mining. The width of the cutting face established according to the present invention is only about 16-30 feet, the conveying means effectively carrying away the coal cut along this relatively narrow face.
Means for supporting the roof and for anchoring the mounting means in stationary position during cutting are provided which allow for maximum flexibility in the movement (advancement) of the miner, while providing roof support as close to the cutting action as possible. Such means preferably include a plurality of vertically-adjustable rams. The rams have elongated top portions thereof which extend to a point close to the cutting face, and within an established dust control area (as opposed to the prior art). Means are also provided for sumping (advancing) the cutting heads when they are disposed in their initial (or any other) positions. The sumping means preferably includes a plurality of horizontally-adjustable rams associated with selected ones of said vertical rams, hydraulic control means being provided for the vertically and horizontally-adjustable rams so that quick advancement of the cutting heads takes place while proper roof support is always provided. Means associated with the supporting means are provided for substantially containing dust generated by cutting into a confined area adjacent the face. As mentioned previously, the supporting means have a portion thereof which preferably is within the confined area and means are provided for exhausting the dust from the confined area to the area for safe disposal thereof.
The dust-containing means preferably includes a curtain assembly including a rubber flap or the like sealing a metal plate(s) or the like with the roof. All the dust in the confined area during cutting is effectively contained therein by the metal plate(s) and its rubber seal. An exhaust fan(s) or the like is mounted in the curtain plate portion of the assembly for drawing the dust through the confined area along the cutting face at a volume rate adequate to provide dust control and face ventilation. Also, a water spray may be provided in the confined area for facilitating dust control and water for the water spray may be provided by cooling water cooperating with electric motors that provide the means for rotating the cutting heads to effect proper cutting.
Collapse of the tunnel in back of the miner is prevented by placing suitable roof supports in back of the miner after each intermittent advancement of the miner by the supporting and sumping means.
It is the primary object of the present invention to provide an improved full face miner, one especially adapted for use in low coal seam mining and one that insures miner safety and complies with applicable federal requirements. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and the appended claims.